EP0091450A4

EP0091450A4 - Method and apparatus for improving the biological utilizability of nutriments.

Info

Publication number: EP0091450A4
Application number: EP19820903051
Authority: EP
Inventors: Jozsef Benedek; Jakab Matyas; Milan Nedelykov; Gertrud Szabolcsi; Tibor Devenyi
Original assignee: INSTITUTE OF ENZYMOLOGY BIOLOGICAL RESEARCH CENTER HUNGARIAN ACADEMY OF SCIENCES; INST OF ENZYMOLOGY BIOLOG RES; VOROS CSILLAG MGTSZ; DIME S GROUP Inc
Current assignee: INSTITUTE OF ENZYMOLOGY BIOLOGICAL RESEARCH CENTER HUNGARIAN ACADEMY OF SCIENCES; INST OF ENZYMOLOGY BIOLOG RES; VOROS CSILLAG MGTSZ; DIME S GROUP Inc
Priority date: 1981-10-06
Filing date: 1982-10-06
Publication date: 1984-03-26
Also published as: HU184483B; WO1983001179A1; JPS58501655A; EP0091450A1

Abstract

Method and apparatus for improving the nutriment by delivering it through a microwave energized area (working area) at an appropriately chosen moisture content, and an appropriately chosen delivery speed using a known transport means. The nutriment is, if necessary, in the first step conditioned to the wanted moisture content and may also subsequently be flavoured before subjecting it to the said microwave treatment under continuous motion. Post-treatment such as grinding, roasting, drying, conserving may also be performed, if wanted. The equipment according to the invention comprises a conditioning chamber, a microwave energizeable working area, and a continuously working transporter such as a gravity path, a vibrational path, or a conveyor.

Description

ME THOD AN D APPARATUS FOR I MPROV I NG TH E B I O L OG I CA L UTILIZABILITY OF NUTRIMENTS

Background of the invention

It is known that the biological utiIizability of nutriments and fodder proteins is even under optimum conditions less than 50 % . Its increasement is of a high economic importance and manifold attempts have been made to find or at least approximate the solution of this problem. The major part of the known solutions Is based on the conception that the decomposition of otherwise hardly digestible or indigestible proteins within the organism, i.e. their proteolysis, may be improved by some kind of denaturing. The increase of digestibility is intermediately also improving the biological utiIizabiIity of the nutriment or fodder protein.

Natural protein is hardly digestible, sometimes indigestible. There a re many ways chemical ones as well as physical ones for denaturing same. The human nutriments are generally consumed in the cooked state: the nutritive protein is during the boiling process in the presence of water denatured and becomes thereby digestible. The heat-treatment of fodder proteins is of a quite different character, it is mainly performed in a dehydrated state of the fodder; water or vapour is only in certain cases present, e.g. during toast uig or extruding. A heat -treatment in the dehydrated state is, however, only slightly effective and even the denaturing of hydrated fodder has only a partical effect if the hydrating has not been performed sufficiently. This is why the acidic denaturing of the fodder proteins is more effective than the heat-treatment of same: this method results in an irreversible change of the configuration of the product and the digestibility and the biological utiIizabiIity is thereby improving.

The most widespread protein carriers for use as food and fodder are all over the world the different legumes and oil-seeds having a protein content of 20 to 40 % and, consequently, a very high food-value. It is also of importance that these nutriments are besides their high protein content also of a biologically very advantageous amine acid composition. Notwithstanding the advantageous protein content and composition of these nutriments, their utiIizabiIity is affected for their including harmful, anti-nutritive substances in a considerable proportion. The treatment of the nutriments such as cooking, other heat-treatment, acidic treatment, fractionating and the like is also intended to diminish the rate of such anti -nutrϊtive substances with more or less success.

The methods belonging to prior art may differently be appreciated dependent on the state of the nutriment (intact seed, grist, extract, special protein fraction).

The unextracted, intact vegetable seeds such as soybean, pea, bean, lentil, rice may immediately be used for alimentary purposes. They a re used after cooking whereas the industrial heat-treatment of same may be considered as pre-cooking in order to simplify and diminish the user's task in the kitchen.

The unextracted, intact seeds may also be used for forage purposes though it is in this case necessary to take into consideration the presence, the character, and the composition of different substances in the seed. In the case of oil-seeds, the vegatable oils are mainly preferred which a re available in large quantities of high value and forming an energy source. The heat-treatment has also in this case a double purpose: improving the digestibility and diminishing the ratio of anti-nutritive substances. It is, however, to be taken into consideration whether other valuable components a re not affected by the heat-treatment (or other treatment) performed with respect to the proteins.

Based on the rich experiences obtained when treating the extracted grist, manifold methods have been conceived for the heat-treatment of intact seeds, too, which have been summarized by White et al (Poultry Sci., 46, 1967, 1180 -1185). The treatment of the intact seeds in different ways such as IR heating, autoclaving, extruding and the like resulted in products of equivalent value as compared with the extracted grists. Other methods of heat-treatment such as dielectric or microwave heating were in this field up till now only applied at Laboratory scale.

The energy balance of the conventional heat -treating processes is disadvantageous considering the important heat Loss. The energy is intermediately applied, it has to penetrate from outside into the seed (in case of grist into the interior of the granule) enforced by the heat effect of the boiling water or the vapour and it is obvious that the whole surrounding is thereby also heated. It is entirely different in case of microwave heating since the radiation effects only the oscillation of the water molecules and heat is only at the very spot of the oscillation forming. If a wet seed is exposed to microwave radiation, the water molecules in the interior of the seed start oscillating and the water is boiling in the interior of the seed; the denaturing by heat and, consequently, the improvement of digestibility and biological utiIizability is, thus, performed without any notable loss.

Microwave heating has in this field generally been applied as a means for drying in an energy saving manner, especially in combination with other treatments. It has, however, sometimes already been applied for increasing the value of the nutriment, e.g. to decrease its myrosinase enzyme activity (Maheshwari et al., JAOCS, 1980, 194-199). There have also been essays with soy grist (Wing et al., Nutrition Report Internat., 4, 1971, 387-396) in the course of which an effect equivalent to the one of a 30 minutes autoclaving could be obtained by a microwave irradiation of only some minutes.

A further method (Gustafson et al., Poultry Sci., 50, 1971, 358-364) was used also at laboratory s.cale for the irradiation of soy -seeds having a Low moisture content whereby a nutriment was obtained having a value equivalent to the one of extracted grist.

There is in the greater part of the world not only a serious shortage of proteins but also the want of' energy is more and more increasing and the efficiency of the use of energy sources is very important considerinc; the incessant rise of the prices for energy carriers. The conventional methods of heat-treatment of nutriments are showing a by far not optimal energy balance so that the economic aspects make the search for novel methods with a lower rate of energy loss inevitable.

It is already known that the microwave treatment is one of the energy-saving heat-treating methods: the microwave treatment effects the oscillation of water molecules inside the wet material so that the heat is forming in situ and the evaporation is moving from the interior of the seed or granule towards the surface; the generated heat Is not heating the surrounding space and the heat loss is, thus, diminished whereas the heat leaving the seed in the course of evaporation may at least partially be recovered by using appropriate devices.

It is the object of the invention to provide a novel method and equipment with technically simple features and an advantageous energy balance for improving the digestibility and, thus, the biological utiIizability of nutritive and fodder proteins, i.e. for preparing products which may immediately be used for food and/or fodder purposes.

Summary of the invention

The invention is based on the conception that the denaturing of alimentary and/or fodder proteins may sufficiently be performed by a very short microwave irradiation (several minutes) of their carriers such as intact seeds, grists, extracts, fractions at industrial scale if their moisture content is at the optimum value. The treatment leads not only to a decrease of solubility but also to a considerable decrease of the ratio of anti -nutrit.ive components, e.g. the trypsin inhibitor content is diminished in case of soybeans; the digestibility and biological utiIizabiIity is thereby considerably increased. Consequently, the microwave treatment may successfully be performed during a continuous motion of the nutritive substances to be treated along the working area so that all steps necessary to bring the starting material into its consumable state including the pretreatment as well as the post-treatment, if any, may sequentially be performed within a short processing period at industrial scale and under advantageous technological conditions

If the raw material is in its natural state of a suitable moisture content, the whole improving process may be restricted to a single step, i.e. the delivering of the nutriment to be treated (hereinafter: charge) through a microwave energized area (hereinafter: working area) by means of a known transporter such as gravity path, vibration path, or belt conveyor the said path crossing the working a rea . The expression working area is understood as an a rea which is along a certain length L_t uniformly irradiated with microwave energy, e.g. the interior of a magnetron wherein the microwave field is effective along a path of L_t length.

If the moisture content of the raw material in its natural state is not suitable, the charge is in the first step conditioned to the appropriate moisture content in any way known from prior art and then is performed the microwave treatment as the second step. A further advantage is obtained if the microwave treatment is preceded by a flavouring operation so that the microwave treatment is applied to a charge containing already the said flavouring and/or odouring (hereinafter: flavouring) agent(s). The flavouring may be performed in the course of the conditioning operation or following same but always preceding the microwave treatment. The importance of incorporating one or more flavouring agents into the charge before performing the microwave irradiation can be understood if taking into consideration the following.

It is well known that a microwave field is exerting both thermic and non-thermic effects upon complex systems, aqueous solutions, polarized solutions, biological systems such as cells, tissues, cell particles etc. The thermic effect is in the case of denaturing vegetable substances more important the same having a moisture content exceeding 10 % . Tests have shown that the insertion of organic and/or anorganic dipole molecules is increasing the non-thermic effects their efficiency depending on the concentration of the said dipoles. The presence of salt and/or other flavouring agents, especially organic compounds, in the charge is improving the denaturing conditions in so far that a sufficient denaturing effect can be obtained at a lower temperature as compared with the treatment of a charge of a similar moisture content (e.g. 10-15 % ) having a similar composition but for the lack of the said flavouring agents

Our tests have shown that an improved energy absorbing effect may be expected if the said dipole molecules are present. Increasing the energy absorption means also increasing the efficiency of the microwave treatment and, consequently, improving the energy balance. A synergic effect due to the simultaneous use of different dipoles (e.g. salt and other kind of flavouring agents) can be observed owing to which both the temperature of the charge during irradiation and the treatment duration may be diminished; the diminution of the treatment duration allows an increase of the delivery speed and, thus, an increase in productivity.

The improved method according to the invention wherein a flavouring operation is (also) performed preceding the microwave treatment has also further advantages. The flavouring may be performed either in the course of the conditioning operation or following same. The variants a re shown in our Examples 20 and 21, respectively. The conditioning and flavouring may, e.g., simultaneously be performed by adding the said flavouring agent(s) to the conditioning steep liquor. In this case, the flavouring agents a re distributed in the hydrated part of the seed which is, of course, only a certain part of the seed. The micro wave irradiation amends the molecular structure of the seed, the proteins become denatured, a small part of the carbon hydrates undergoes hydrolitic degeneration. As a consequence of this process and the simultaneous drying process, the hydrate rinds within the seed a re also changing, the structure slackens, and the distribution of the flavouring agents is covering the whole cross-section of the seed. This metamorphosis leads to that the interior of the seed becomes an almost uniformly crispy medium which is showing a virtual homogenity towards the human sense organs whereas no rind formation is appearing at the surface of the seed. Seeds flavoured or roasted in the conventional way are, however, only at the surface region undergoing a flavouring amendment (e.g. forming a salt layer) and the thin rind forming during the conventional roasting process is preventing the diffusion of the flavouring agent(s) into the inner regions of the seed. If a seed is e.g. salted this way, the taste is at the beginning of consuming it an intensively salty one for the dissolving of the surface salt layer in the mouth. The salt quantity forming such a Layer may hardly be controlled and is mainly dependent on the dimension of the single seed and the homogeneity of the dimensions of the different seeds. If, however, the flavouring is performed according to the invention, the flavouring agents are distributed along the interior of the seed and the quantity of the different flavouring agents within the seed is mainly dependent on the one hand upon the concentration of the single components of the steep liquor and on the other hand upon the duration of the steeping.

If the flavouring is performed after the conditioning step, the microwave treatment will be the third step.

It can be seen that this way a small increase of the preliminary treatment period is not only offering the opportunity of diminishing the microwave treatment period but also in so far advantageous that a nutriment can be obtained after the microwave treatment which may immediately be consumed and is of an outstandingly delicious taste.

It can also be seen that the flavouring agents may simply be added to the suitably conditioned charge under stirring. Common salt, sugar and the like may be used as preferred flavouring agents. A great variety in shade of different tastes may be obtained by choosing appropriate additional flavouring agents such as. onion, garlic, chili, pepper, curry, coffee, cocoa and the like.

A further improvement can be achieved if in case of legumes the microwave treatment is preceded by an enzyme treatment as set forth hereinbelow. This treatment is intended to remove the so-called flatus factor as fas as possible. The flatus factor - a small group of trisacharides present in legumes - do not belong directly to the antinutrItive compounds, but may considered as non convenient constituents, since cousing discomfort feelings in the consumer. These compounds a re not heat sensitive, this is why heat-treatment is unsuccesful.

However, these compounds a re acid-sensitive ones: arround pH = 2 hydrolysis occurs and they are converted to monosacharydes. During this process naturally the amount of flatus factor is decreasing, which can be monitored by thin layer ch roma tog raphy or by gas -chromatography. Since the protein fraction in legumes represents a large buffer-capacity, a relatively great amount of mineral acid is necessary to install pH = 2. In the case of human comsumption this should be eliminated or neutralized. The process of decreasing the amount of flatus factor is rather complicated, an especially suitable solution of this problem is the enzyme treatment described in the patent procedure.

Regarding the patent procedure in the case of legumes the conditioned object, following the conditioning, but in any cases before microwave treatment, is incubated preferably in a solution, which contains in water or in a 0.1-0.5 % solution of sodium bicarbonate technical grade invertase or so called raffinose splitting enzyme, i.e. -ga lactosidase enzyme. The temperature of the incubation might be between 16 and 60 C° and is inversely proportional with the incubation time which is depending from the temperature between 24 and 8 hours. As a consequence of the treatment the fiber containing shell separates from the seed, the structure of the strongly swollen seed becomes loose and the penetrating enzyme splitts the trisacharydes. After the enzyme treatment the seeds can be flavoured as described before. If sodium chloride is used for flavouring, the enzyme treatment can be achieved in the presence of salt since it does not inhibit the enzymatic activity. If necessary, following the enzymatic treatment further flavouring compounds can be added to the object before microwave treatment.

Post-treatment such as grinding, drying, roasting, conserving (freezing) may also be performed after irradiation.

The main operation in the method according to the invention is the microwave irradiation performed during a continuous motion of the charge.

If the amount of microwave energy supplied into the working area during a time unit is known, men ordinary skilled in the art may therefrom derive the required minimum treatment duration T_k/W/ which is necessary to obtain the wanted improvement in biological ut i I i zab I I ϊ ty of the charge and also the permissible maximum treatment duration T_m/W/ which is not yet detrimental to the charge. The range of the delivery speed v_sz may, thus, be specified as

The equipment according to the invention is designed in a manner as to perform the method as set forth hereinabove. It comprises a conditioning chamber, a microwave working area and a feeder, and the improvement consists in that the feeder comprises a transport channel crossing the said working a rea and a continuously working transport means such as a cavity path, a vibratϊonal path, o r a belt conveyor.

Description of the preferred embodiments

In a preferred embodiment of the method according to the invention, at least one mineral salt or mineral acid such as IN hydrogen chloride is added to the charge during the conditioning.

In a preferred embodiment of the equipment according to the invention, the effective delivery cross-section Q_k of the transport channel (measured in a plane lying perpendicularly to the movement of the charge) is about: Q_k =λ(4x λ )4, wherein λ is the wavelength of the exciting microwave energy.

The above specified interconnections between the delivery speed v_sz, the required minimum treatment duration T_k /W/, the permissible maximum treatment duration T_m/W/, the optimum energy level, the dimensions of the channel crossing the working area, etc. may be taken into consideration when designing an equipment for a certain application even if the means exciting the microwave energy is not a single compact device but there a re more than one uniformly designed magnetrons coupled serially and/or parallelly to form a generator cascade.

It is well known that the energy transmitting device generally used in the microwave power electronics, viz. the magnetron is relatively cheap until its power range does not exceed. the limit of about 2 kW whereas an abrupt increase of the price occurs once the power range is exceeding this limit, 50 to 60 1 kW magnetrons may be bought for the price of a single 10 kW magnetron. The use of high power magnetrons is very expensive not only for the high price of the magnetron itself but a further increase in expenditures is caused by the use of high power-high voltage transformers, switches, rectifiers, condensers, etc, The microwave energy is preferably supplied to the working area by continuous pumping. The use of small power magnetrons coupled serially and/or parallelly in a sufficient number to provide the necessary working power is preferable not only for the said technological-economical reasons but also for biological reasons, I.e. because the denaturing process as set forth above has optimal effect in the microwave field strength range of about 500 V/cm whereas a higher intensity may cause burning phenomena.

This ponderation is based on a further conception. We realized that the effectiveness of the irradiation is dependent on the geometrical shape of the layer to be irradiated; the behaviour is different if choosing a maximum width or a maximum layer thickness, respectively. If soybean- is conditioned to the necessary moisture content, the increase of the layer thickness is increasing the decomposition of the inhibit ing substances, and accordingly the digestibility and biological utiIizabiIity of the charge whereas the efficiency of the microwave irradiation is again decreasing if the width is increased beyond the said optimum value which may be observed by measuring the ratio of anti-nutritive substances in the treated charge or the degree of digestibility.

We found that a uniform denaturation occured over the whole charge if the charge crossed the Line of the microwave nodes in a channel the cross-section Q_k of which did not exceed the Q, =λ (4x λ.)4 value; this value should therefor not be exceeded but it is expedient to extend the dimensions to this limit.

It is an outstanding advantage of the method according to the invention that this kind of heat-treatment ( =denaturing) is not detrimental to the valuable substances included in the protein-carrier such as fatty acids. In the course of treating soybeans, we observed an eightfold increase in digestibility, an improvement of the stimulant features (flavour, odour, etc.), and we observed at the same time no quantitative or qualitativ. change in the recovery of oil and in the fatty acid composition (C_16' C_{16: 1'} C_18' C_{18: 1 ,2,3'} C_20' C_{20: 1}) as compared with raw soybeans which have not been treated in the above described manner.

The same has been observed with the amino acid composition of the hydrolized, acidic protein-carriers; the amino acids were not affected by the microwave irradiation.

An important feature of the efficiency of the treatment is the decrease of the ratio of anti-nutritive substances. This may with the greater part of plants, and especially with soybeans and other oil-seeds be tested by measuring the presence of trypsin inhibitors. The digestibility may be tested in vitro (following in a slightly amended manner the method published by Szabolcsϊ and Szörényi, Acta Physiol. Hung., 9, 1956, 293). The method according to the invention may advantageously be applied in treating the plants having a higher protein content such as legumes as bean, pea, soybean, lupin, wild pea, and oil-seeds such as seeds of sunflower, peanut, cotton, rape but even corns, rice, maize, and products thereof. The method according to the invention may be applied if such nutriments shall be pre-cooked or conserved. If such nutriments shall be used as forage, they may after the treatment according to the Invention immediately be used, e.g. in the pig and calf breeding.

The optimum efficiency may be obtained by using a set of small power magnetrons as microwave sources which may be coupled serially and/or parallelly and by a suitable choice of the dimensions of the working area.

It is expedient to control the moisture-content during conditioning in a manner that no further drying should be needed after the microwave treatment but sometimes a subsequent treatment may be necessary.

The microwave treatment destroys such substances of the treated vegetable nutriment which a re harmful during its storage, e.g. cause rancidity. The treatment is therefor extending the permissible storage duration of the products.

We have treated soybeans at a moisture-content of 20 % for only 3 minutes with microwave irradiation and found that the trypsin inhibitor content practically vanished (where a residuum of same could be observed, it ammounted to less than 10 % of the content before treatment).

The digestibility was measured in vitro applying in order pepsin, trypsin and chymotrypsin and we found that it increased after the microwave treatment to four times its initial value. The protein content of the soybean showed after a conventional heat-treatment of 150 minutes a 8 % digestibility, the protein content of extruded soy flour showed a 15 % digestibility whereas the microwave treatment according to the invention resulted in a 34 % digestibility of the protein content under the test conditions as set forth hereinbefore. The following examples are affirming this experience. The conditioning is in all examples performed in the same way, the sample being enclosed in a welded polyethylene bag. The treatment is performed by delivering the sample along a path irradiated by a 1.5 kW magnetron. The measured features are specified as percentage of the values measured before treating (hereinafter: initial value).

Example 1

Soybean is conditioned to a 20 % moisture content. The seeds are incubated for 3 hours at room temperature and for 16 hours at + 4 °C temperature. The conditioned seeds are delivered along the irradiated path at a 33.3 cm/min. speed.. The treated seeds a re grinded and then dried for 16 hours at 45 ºC temperature. The trypsin inhibitor content was measured to give 8 % of the initial value

Example 2

Soybean is conditioned to a 20 % moisture content and then irradiated but the delivery speed is 66.6 cm/min. The trypsin inhibitor content of the treated sample is 15 % of the initial value.

Example 3

The soybean is conditioned to a moisture content of 18 %, the delivery speed is 33.3 cm/min. The trypsin inhibitor content sank to 7 % of the initial value. The digestibility increased to four times the initial value.

Example 4 Maize is conditioned in the same manner but for adding IN hydrogen chloride during conditioning. The delivery speed during irradiation is 15 cm/min. The degree of the hydrolizing process may be established by measuring the maltose concentration to give 25 times the initial value.

Example 5

Fodder pea is conditioned to a 20 % moisture content and then irradiated at a delivery speed of 33.3 cm/min. The digestibility of the sample is 3.5 times the initial value.

Example 6

Edible bean is conditioned to a 16.7 % moisture content and then irradiated at a delivery speed of 66.6 cm/min. The digestibility became 2 times the initial value.

Example 7

Edible rice is conditioned to a 15 % moisture content and irradiated at a delivery speed of 15 cm/min. The necessary cooking time has been reduced to 5 minutes whereas the initial value has been 35-40 minutes.

Example 8

Soybean having a protein content of 35.4 % and a natural moisture content of 11.2 % is delivered along the irradiated path at a delivery speed of 66.7 cm/min. The treated sample showed a diminution of the moisture content to become 6.5 %, and of the trypsin inhibitor content from 46.9 to 2.5 TlU/mg.

Example 9

Soybean having a protein content of 35.4 % is steeped in water at a temperature of 65 ºC for 90 minutes. The moisture content increased up to 60 % . The thus treated sample is delivered along- the irradiated path at a delivery speed of 66.7 cm/min. The trypsin inhibitor content showed a diminution from 47.2 to 3.0 TlU/mg. The product is freezed to storeability in a known manner. Example 10

Soybean having a protein content of 35.4 % is thoroughly washed under a warm water-jet and then steeped in water at a temperature of 60 ºC for 90 minutes. Common salt is added under stirring at a rate of 40 g per 1 kg of soybean having a moisture content of 60 % . The flavoured sample is then delivered along the irradiated path at a speed of 8 cm/min. The product became crispy and salty and its trypsin inhibitor content diminished from the starting value.of 46.9 to 2.5 TlU/mg. The composition of the product is shown in Table I as compared with the one of the starting materiaI.

In Example 11 to 17, the first step, the conditioning is performed according to Example 10. The further treatment is particularly set forth for each sample.

Example 11

The flavouring of the soybean sample is also performed according to Example 10. The wet sample is irradiated at a delivery speed of 66.7 cm/min, and then dried, resp. roasted according to prior art. The advantageous change in the structure of the seed as set forth in Example 10 is obtained but the product is of a darker colour a thin crust having been formed at the surface after roasting. Example 12

100 g common salt is under stirring added to 1 kg conditioned horse-bean (vicia faba) and then the irradiation is performed at a delivery speed of 8 cm/min. No trypsin inhibitor could be detected in the product. If the digestibility of the starting material is considered as 100 % basis, the digestibility of the treated sample amounts up to 258 % . The thus treated bean is crispy and of a delicious taste.

Example 13

The treatment is the same as in Example

12 but for using a delivery speed of 66.7 cm/min, and drying and roasting the treated seeds in a known manner.

Example 14

120 g granulated sugar is under stirring added to 1 kg of conditioned soybean. The delivery speed is 8 cm/min. The product is sweety, crispy, mildly caramelized, its composition is according to Table I.

Example 15

The treatment is the same as in Example 14 but for using a delivery speed of 66.7 cm/min, and drying and roasting the treated seeds in a known manner.

Example 16

100 g granulated sugar is under stirring added to 1 kg of conditioned horse-bean. The delivery speed is 8 cm/min. The product is sweety, crispy, mildly caramelized.

Example 17 The treatment is the same as in Example 16 but for using a delivery speed of 66.7 cm/min, and drying and roasting the treated seeds in a known manner.

Example 1-8 1 kg soybean is mixed up with 20 g sodium hydrocarbonate, 3 liter water, and 200 g carved garlic to steep the charge for 16 hours. The steep liquor is then decanted and 80 g common salt is added to the soybean. The charge is irradiated at a delivery speed of 66.7 cm/min, and dried and roasted in a known manner.

Example 19

The treatment is the same as in Example 18 but for adding 600 g carved onion instead of the 200 g garlic to the mixture.

Example 20

1 kg soybean is mixed up with 3 liter water and 80 g common salt to steep the charge for 16 hours. The steep liquor is then decanted and the charge is irradiated at a delivery speed of 66.7 cm/min, and dried and roasted in a known manner.

Example 21

1 kg soybean is mixed up with 3 liter water to steep the charge for 16 hours. The water is decanted and 80 g salt and 160 g onion powder is added to the wet soybean. The charge is then irradiated at a delivery charge of 66.7 cm/min, and dried and roasted in a known manner.

Example 22

The treatment is the same as in Example 21 but for adding 100 g dried garlic powder instead of the onion powder to the mixture.

Example 23

1 kg dried pea is mixed up with 3 liter water and 20 g sodium hydrocarbonate to steep the charge for 16 hours. The steep liquor is then decanted and the charge is irradiated at a delivery speed of 66.7 cm/min, then the product is freezed in a known manner.

It can be seen from the examples that the moisture content may vary within a very broad range. The conditioning is usually performed in the 15-35 % range, preferably in the 18-22 % range and most preferably at 20 % . The flavouring may also manifold be varied. Typical flavouring agents a re enlisted in Table II.

Example 24

1 kg soybean is mixed up with 3 liter 0.05 % yeast invertase solution and is incubated for 24 hours at room temperature. The supernatant water phase is decanted and the seeds a re mixed up with salt or other flavouring material and after soaking microwave treatment is performed in a known manner.

Example 25

The treatment is the same as in Example 24 but for adding the enzyme 0.5 % sodium bicarbonate solution instead of water.

Example 26 The treatment is the same as in Example 24 but for using raffinose splitting enzyme ( -ga lactosidase, technical grade) instead of yeast invertase.

Similarly to the Examples described above enzyme treatments using different temperatures were elaborated also. Incubation for 16 hours at 37 Cº, incubation for 8 hours at 45 Cº can be applied. All experiamentaI conditions can be used if the enzyme concentration is 0.1 % in the solut ion.

In Fig. 1 the conditioned charge to be denatured is continuelly delivered to the inlet end 12 of the working area 13 by the belt conveyor 11, then proceeds through the working area 13 crossing thereby the nude(s) of the field. The working are 13 is preferably shaped in a manner that only one nude be formed along its longitudinal axis so that the energy concentration may be optimal in accordance with the equation given hereinbefore and the delivery speed v_sz is expediently sought for in trial run to obtain an optimum efficiency.

Another way of feeding the equipment continuously is shown in Figure 2 in case of a one magnetron embodiment. A cylindric TM_01p mode cavity resonator 23 is used and a descend pipe 24 provides for the continuous feeding. The charge enters the throat 25 of the teflon based descend pipe 24, is falling along the vertical delivery path and through the vibrational valve 22 upon the belt conveyor 21 delivering off the already treated charge. The exciting unit 27 is over the waveguide 26 coupled with the working area of the cavity resonator 23 (the latter one is not shown only symbolized by its object-line bordering the vertical delivery path).

Figure 3 is showing that the magnetrons 32 which are elements of the exciting system may be arranged along the delivery path 31 and may be coupled either serially along the length of the working area or parallelly along the width of the working area and they may also be coupled partially serially and partially parallelly and appropriately arranged just according to the wanted energy distribution.

The field configuration shown in Figure 4 is characteristic for the TM_{01 p} mode oscillation . The descend pipe 41, the electric force lines 42, the magnetic force lines 43, and the cylindric cavity resonator 44 a re re fe r red to for a better understanding of the design principle.

That part of the delivery channel which may during the transport partially or entirely be filled up with the charge may be characterized by its efficient cross-section. If, e.g., the transport means Is a belt conveyor, the width of the surface of the conveyor belt which is bordered by its margins may be considered as the efficient width, the permissible loading height of the charge as the efficient height, and their product as the efficient cross-section of the delivery channel. If the charge is falling through a descend pipe, the cross-section of the pipe is the efficient cross-section of the delivery channel. In a preferred embodiment of the equipment according to the invention, the efficient delivery cross-section Q_k measured in a plane lying perpendicularly to the movement of the charge is about

Q_k = λ (4x λ )4, wherein A is the wavelength of the exciting microwave energy. The number N of magnetrons forming in serial and/or parallel coupling the exciting cascade is generally: 2 ≤ N ≤ 20.

If the vapour forming in the working area is led back to the vicinity of the heat exchanger arranged in or next to the conditioning chamber, the greater part of the heat accumulated in the said vapour may again be recovered and used in the pre-heatiπg of the charge. The greater part of the heat accumulated in the cooling medium of the magnetron may also be recovered and used if the cooling medium pipeline is coupled with the heat exchanger arranged in the starting tract of the delivery path of the charge, i.e. in the vicinity of the conditioning chamber or the inlet of the working area, respectively.

The main advantages of the invention, i.e. both the method and the equipment are the foIlowing: a) The digestibility of the protein carrier and, thus, the biological utilization of the protein carriers may considerably be Improved by the microbiological treatment of seeds and grists or products thereof In situ, with a positive energy balance and without any notable heat loss.

b) The treatment performed in a suitable equipment results in a considerable diminution of anti-nutritive substances in the nutriment so that the product may immediately be consumed either as food or as fodder.

c) The permissible storage duration of the nutriment may be extended since in the course of the treatment, some harmful components of the nutriment are damaged, e.g. the enzymes accelerating the rancidifϊca tion a re becoming inactive as a consequence of the in situ denaturing according to the ϊnvention.

d) The treatment is relatively inexpensive until no high power magnetron is used but only magnetrons of a power not exceeding 1 to 2 kW.

e) Both the method and the equipment a re of an outstandingly simple character and may, therefor, easily be combined with previously or subsequently needed further technological steps such as pre-heatiπg, transporting, grinding.

Claims

AMENDED CLAIMS

(received by the International Bureau on 28 March 1983 (28.03.83)) 1-13 (cancelled)

14. (new) A method for improving the biological uti lizabi lity of materials of vegetable or animal origin which may be used as human or animal nutriment, in the course of which the starting material (hereinafter:charge) is after conditioning same subjected to microwave irradiation performed preferably by conveying the said charge through a microwave irradiated area such as the cavity of a magnetron, wherein the improvement consists in that the said microwave treatment is preceded by adding - in the course of the conditioning step one or more flavouring agents such as common salt or sugar to the charge.

15. (new) A method as claimed in claim 14 wherein the charge i s a legume and i t i s - preced i ng the mi crowave treatment treated in a steep liquor containing a yeast invertase enzyme or a so-called raffinose splitting enzyme, i.e. a gelectosidase in a concentration from 0.005 to 0.1 % .

16. (new) A method as claimed in claim 15 wherein the enzyme treatment is performed after completion of the flavouring operation.

17. (new) A method as claimed in claim 16 wherein the enzyme treatment is performed in a steep liquor containing sodium chloride in a concentration sufficient for flavouring the charge and the enzyme treatment is optionally followed by adding other flavouring agent(s) to the charge before performing the microwave treatment.